An average person spends about one-third of his or her life asleep. Sleep is the time our bodies undergo repair and detoxification. Research has shown that poor sleep patterns is an indication of and often directly correlated to poor health. Proper, restful and effective sleep has a profound effect on our mental, emotional and physical well-being.
Every person has a unique circadian rhythm that, without manipulation, will cause the person to consistently go to sleep around a certain time and wake up around a certain time. For most people, a typical night's sleep is comprised of five different sleep cycles, each lasting about 90 minutes. The first four stages of each cycle are often regarded as quiet sleep or non-rapid eye movement (NREM). The final stage is often denoted by and referred to as rapid eye movement (REM). REM sleep is thought to help consolidate memory and emotion. REM sleep is also the time when blood flow rises sharply in several areas of the brain that are linked to processing memories and emotional experiences. During REM sleep, areas of the brain associated with complex reasoning and language experience blood flow declines, whereas areas of the brain associated with processing memories and emotional experiences exhibit increased blood flow.
During a sleep, the person's body temperature will also continue to fall throughout the night. For instance, often time a person's body temperature during the early morning (e.g., around 5:00 am) is usually one degree centigrade below his or her body temperature the evening before when they first went to sleep. Lower body temperature is believed to assist in and/or linked to deep/restorative sleep that allows the body a chance to rest and rebuild itself. As body temperature rises, deep sleep is more difficult to achieve and maintain.